Immature Peregrine Falcon / © Bryan Pfeiffer
TODAY ON MONHEGAN ISLAND the winds blew fair with birds. Peregrine Falcons gave chase and took life. In the lilacs near the Rope Shed a Nashville Warbler cavorted with a Tennessee Warbler. A flock of a dozen Baltimore Orioles paraded around the village.
Another day on the flyway.
Twenty or so species of warbler, six species of vireo, oddballs like Common Nighthawk, Red-headed Woodpecker and Lesser Black-backed Gull have kept us birders busy and entertained this week. I myself am much too busy to spend more time here writing. My apologies for that. I’ll offer a few photos and promises of a bird list soon. Meanwhile, here are all my Monhegan Migration updates. Onward.
Red-eyed Vireo / © Bryan Pfeiffer
Painted Lady / © Bryan Pfeiffer
Cape May Warbler / © Bryan Pfeiffer
A Wandering Glider (Pantala flavescens) off Black Head on Monhegan Island
ON NORTH WINDS Wednesday morning the songbirds came to Monhegan – and then they left. Our gentle rain of migrants included newly arrived (or newly discovered) Yellow-throated Vireo, Blue-winged Warbler (thanks to Tony Vazzano) and Cerulean Warbler, an extraordinary bird for the island (last seen at the Ice Pond and, I believe, discovered by the Audubon Hog Island birding group). Blue Grosbeak, Lark Sparrow and Clay-colored Sparrow, the usual Monhegan oddballs, entertained the besotted birders. By late morning, many of the birds seemed to have launched back toward the mainland, or “in shore” as islanders put it, to regain their southbound orientation.
Ruth and I spent the afternoon, as usual, walking Monhegan’s perimeter. Along the way we encountered insects – lots of them, including that Wandering Glider above, a dragonfly found on every continent except Antarctica and an animal of immeasurable accomlishment. Wandering Glider can cross oceans. It’s the albatross of insects. I’d report more on Wandering Glider, but you’ll have to read the book about this dragonfly (that’s taking me forever to write). Even now, the birds beckon. I’m out the door. I’ll write more when I can find more time to work (hard to do on Monhegan, except for the hardworking people who live here).
I’ll leave you with two other spineless invertebrates from yesterday. First, one of the Red Admirals darting around the island. Many of you know these butterflies, which also migrate: from above they are bittersweet chocolate with cherry bands. But, oh, the underside. It’s a Monhegan painter’s palette. Yeah, a Cerulean Warbler, not seen by many, is a damned good bird on Monhegan. But a Red Admiral, displaying daily for anyone who cares to look … well, you decide. It’s below.
Next, and the coolest thing we saw yesterday, were these little specks of lint with “tails.” Sally Boynton saw them at Dead Man’s Cove. A few made their way in seawater to a bowl on the counter at the Lupine Gallery (the premire place for art on Monhegan), where Sally’s brother Bill and co-owner Jackie Boegel tended to them for the day – and sleuthed them out as immature jellyfish. Jackie discovered that jellyfish are booming this summer, perhaps a consequence of a warming ocean.
We wondered what to call these young jellyfish. I suggested “smuckers.” Bill had a better name – “pectins.” Gotta run. More later …. Read all my Monhegan Migration posts here.
Red Admiral (Vanessa atalanta), as you mostly know it.
Red Admiral as a painter might know it.
Jellyfish young — or, as Bill called them, “pectins.”
Ocean Sunfish / © Bryan Pfeiffer
TO BORROW AN ENTIRE CHAPTER from William Faulkner: My favorite is a fish.
Even though we saw more Cape May Warblers than Yellow rumped Warblers; even though Northern Gannets are plunge-diving everywhere offshore; even though Philadelphia Vireos present themselves with such elegance; even though Philadelphia Vireos make me swoon and happy; even though a Sharp-shinned Hawk chased a Belted Kingfisher by our deck during brunch; and even though we watched a couple of Minke Whales drift past Black Head; my favorite encounter during our first day with fall migrants on Monhegan Island, Maine, was the Ocean Sunfish off White Head.
This is a crazy animal. It eats mostly jellyfish. And because jellyfish aren’t exactly nutritious, an Ocean Sunfish eats a lot of jellyfish. So it gets big and fat on jellyfish, weighing in at an actual ton or more. We often see Ocean Sunfish “sideways,” like a flounder, but Ocean Sunfish do swim like any self-respecting upright fish. The basking behavior is so that seabirds can pick parasites from the skin of this fish – or so the hypothesis goes. (Before I leave this Earth, I want to see an albatross pluck a parasite from an Ocean Sunfish, but not as much as I want to see a Kelp Gull eat the flesh of a surfacing South Atlantic Right Whale.)
Meanwhile, in addition to the whales and fish and seals, we’re seeing songbirds. Not many migrants arrived on today’s strong northwest winds. But we’ve got warblers in ones and twos. You know you’re having a good morning when the first warbler you see is a Cape May (near the Rope Shed). At least two more were in the spruce just up from the Wharf, one of the most reliable spots on the island to find Cape May Warbler.
Ruth and I are in LPBM – Low-Powerd Birding Mode. We’re walking a lot, reading, napping, chasing dragonflies and generally waiting for the birds to come to us. Here’s the opening warbler list:
- Northern Parula
- Yellow Warbler
- Chestnut-sided Warbler
- Magnolia Warbler
- Cape May Warbler
- Yellow-rumped Warbler
- Black-throated Green Warbler
- Blackpoll Warbler
- Black-and-white Warbler
- American Redstart
- Northern Waterthrush
- Common Yellowthroat
- Wilson’s Warbler
All the other usual mid-September Monhegan regulars are here, including Merlins chasing Northern Flickers and full-frontal views of nearly all those warblers. No shearwaters on the crossing from Port Clyde. I’ll post a complete bird list in a day or two.
In insect news, Monarchs accompany us nearly everywhere on the island, along with lots of Red Admirals darting around. Today’s dragonflies included (more to come once I start swinging the net):
- Common Green Darner (Anax junius)
- Shadow Darner (Aeshna umbrosa)
- Black-tipped Darner (Aeshna tuberculifera)
- Canada Darner (Aeshna canadensis)
- Wandering Glider (Pantala flavescens)
- Autumn Meadowhawk (Sympetrum vicinum)
Oh, other big news: Matty’s got Hot Fat open again! Stay tuned for a restaurant review. I’ll check out what’s on tap at Monhegan Brewery. And Monhegan is wrapping up celebration of its Quadracentennial. How many places in the US can you celebrate one of those? I’ll be posting regular “Monhegan Migration” updates (so you can bookmark it) here: http://bryanpfeiffer.com/monhegan-migration
Meanwhile, below are crappy photos of one of the Phily Vireos, one of the Minkes and the sunset from our deck at 7:05PM. (By the way, chapter 19 from Faulkner’s incredible “As I Lay Dying” reads in its entirety: “My mother is a fish.”)
Philadelphia Vireo / © Bryan Pfeiffer
Minke Whale / © Bryan Pfeiffer
The full mooon rising over a ridgeline in Montpelier, Vermont, on Monday seemed to be a big hit on social media this week. So here’s a reprise. Next full moon: October 8.
A Common Green Darner (Anax junius) / © Bryan Pfeiffer
On a crisp, sunny day in September, after what was probably a typical summer for a dragonfly (which involves flying around, killing things and having sex beside a pond), a Common Green Darner took off and began to migrate south. As it cruised past the summit of Vermont’s Mt. Philo, with Lake Champlain below and the Adirondacks off in the distance, the dragonfly crossed paths with a Merlin.
The Merlin, a falcon that kills in flight, swerved, plucked the dragonfly from the sky with its talons and began to eat on the wing. As the falcon and its prey continued southbound, all that remained in their wake was a single dragonfly wing, falling like an autumn leaf toward fields of goldenrod and aster at the base of Mt. Philo.
Eagles, hawks, falcons and Monarch butterflies aren’t the only migrants moving south past mountains this fall. Joining them are dragonflies. Although biologists know plenty about the fall raptor and Monarch migrations, we are only beginning to discover, with some creative chemistry, where these dragonflies go (at least those not killed in flight) and how migration figures in their conservation.
Fly or Die
Most dragonfly species do not migrate. In fact, most are now dead, having already mated during the summer season, leaving behind eggs or larvae to survive the winter. The killing frost will finish off much of what’s still on the wing. But some survivors will leave.
Wandering Glider (Pantala flavescens) / © Bryan Pfeiffer
Among the 460 or so dragonfly and damselfly species native to North America, at least five are classic migrants: Common Green Darner (Anax junius), Black Saddlebags (Tramea lacerata), Wandering Glider (Pantala flavescens), Spot-winged Glider (Pantala hymenaea) and Variegated Meadowhawk (Sympetrum corruptum). Each species is on the move this fall.
Dragonflies migrate for the same reasons other animals migrate: to avoid inhospitable conditions, in this case habitats that freeze or become too cold for the dragonflies themselves or their insect prey. Monarchs go to Mexico. Broad-winged Hawks leave for wintering grounds stretching from southern Mexico into South America. Dragonflies head south to who knows where.
Having studied birds for two centuries, biologists know well their breeding and wintering distributions , even to the point of learning the destination of a particular warbler or sparrow after it leaves us in the fall. Ornithologists catch lots of songbirds in nets and place around one leg a tiny silver bracelet embossed with a unique number – an avian social security number – and then release the birds to the winds. A small percentage of them, still sporting their bracelets, are later recaptured while in migration or on wintering grounds thousands of miles away. Better yet, we’re putting small electronic transmitters on large birds, such as Bar-tailed Godwits and American Woodcocks, and tracking their movements real-time with satellites.
A tagged Monarchs before heading off toward Mexico.
We can even track the movement of a single butterfly. I myself have placed little stickers, each bearing a unique alpha-numerical code, on the hind wings of more than 1,000 Monarchs here in Vermont and elsewhere in North America, and then set each one free to fly toward Mexico, where many are later encountered by conservationists searching for the buttterflies once they arrive in Mexico. With each recovery, we learn more about Monarchs and how they migrate.
The “Heavy” Hydrogen
Dragonflies aren’t so obliging. For one thing, we’re clueless about where they go. Monarchs concentrate each winter in stands of Oyamel Fir in mountains west of Mexico City. So we know where to find them and how to protect them. Tagging or somehow marking a dragonfly would be like putting a message in a bottle and tossing it out to sea. Actually, I suspect we’d find the bottle before the dragonfly.
Yet it turns out that we need not tag or otherwise mark these migratory dragonflies because they themselves carry clues about where they have been. If the Merlin doesn’t get it first, we can catch any migrating dragonfly, analyze trace elements in its tissue and determine roughly how far it has flown.
Our marker is water, more to the point the two hydrogen atoms in water. Recall from high school chemistry that hydrogen nucleus normally contains a single proton and no neutron. But a tiny fraction of hydrogen atoms around the world carry one proton and one neutron. We call it “heavy hydrogen,” or deuterium. And unlike other such atomic variations among elements (which can be radioactive), deuterium is stable in the environment – a “stable isotope”– and stable in the wing of a dragonfly.
Credit: Migratory Dragonfly Partnership
The amount of deuterium in water varies somewhat predictably in North America. You can map it. The ratio of deuterium to hydrogen in water falling as rain or snow changes on a gradient corresponding roughly with latitude. Water in Alberta, for example, carries a different deuterium-to-hydrogen ratio than water in Alabama.
Because dragonflies grow up as nymphs in water, they incorporate the local deuterium ratio into their tissue. It’s like a dialect that a dragonfly bears for life – whether as a nymph in water or a free-flying adult in migration. A Common Green Darner on the wing over Mt. Philo or Miami unwittingly carries a particular deuterium ratio, a birth certificate that tells us generally where it grew up. You are what you eat – or drink.
This science isn’t perfect. We can’t pinpoint a dragonfly’s natal waters in the way we know where a banded bird hatched or a tagged Monarch emerged. But stable isotopes are helping us track the range of migrating dragonflies. It’s “better living through chemistry.” After all, we can’t really know a bird or butterfly or a dragonfly – and what it might need in the way of conservation – until we know all the places it lives or wanders. My colleagues at the Vermont Center for Ecostudies in Norwich, Vermont, are major players in the deuterium-dragonfly work.
By the way, you need not be a chemist to help track dragonfly migration. We’re counting dragonflies in the same way we count migrating raptors during hawkwatches each fall. Learn how to do it and report what you find with help from the Migratory Dragonfly Partnership.
And while we’re out there counting, if a Merlin happens to catch a dragonfly first, you can still make a difference: dash out and catch one of those dragonfly wings falling slowly toward Earth.
Palm Warbler / © Bryan Pfeiffer
AH, THE CLEANSING NORTH WINDS OF AUTUMN. They’re bringing us songbirds. On these cooler mornings you’ll find warblers nearly anywhere. So stop before you get into the car for work. Listen for tiny call notes – this chips, peeps, zeets and whits of fall songbird migration. Here’s my warbler haul (16 species) from weekend stops near Little Elmore Pond in Elmore and Peacham Bog in Groton State Forest:
- Northern Parula
- Tennessee Warbler
- Nashville Warbler
- Chestnut-sided Warbler
- Magnolia Warbler
- Black-throated Blue Warbler (still singing)
- Blackburnian Warbler
- Yellow-rumped Warbler
- Black-throated Green Warbler (still singing, sort of)
- Palm Warbler
- Pine Warbler
- Bay-breasted Warbler (including an exquisite fall adult male)
- Blackpoll Warbler
- Black-and-white Warbler
- Common Yellowthroat
Here’s a Black-throated Blue Warbler in spring. Nice thing about this species is that it looks about the same in the fall. No “confusing fall warbler” here, as Roger Tory Peterson had called them.
Sanderlings / © Bryan Pfeiffer
ON THIS LABOR DAY, you need not labor over shorebirds. As sandpipers and plovers head south this month, I’ll remind you of my Solving Shorebirds post – a guide for landlocked birdwatchers. For those of you already skilled at shorebird identification, take my Shorebird Challenge – a half-dozen quiz photos. Some are tough.
Meanwhile, to mark the 100th anniversary of the
demise eradication of the last Passenger Pigeon, the Cornell Lab of Ornithology’s John Fitzpatrick writes in The New York Times about birds and people at risk. Here’s an example of what he means:
“Why should we care about these aridland birds, or any birds? It’s a common question, as elected officials and voters weigh conservation investments alongside health care, immigration and economic issues.
Besides our moral imperative to maintain the earth’s beauty and bounty for future generations to enjoy, it is important to view birds as accessible indicators of the health of our lands and waters. Take those declining meadowlarks as one example: In my home state of Minnesota, where meadowlarks commonly sang atop utility poles back in the 1950s, the patches of wild grasslands they depended on are now horizon-to-horizon farm fields. As a consequence, barges now get stuck in sediment-filled portions of the Mississippi River because grasslands no longer intercept silt-laden runoff waters from farms. The toxic algae bloom in Lake Erie that recently rendered Toledo’s water supply undrinkable had a similar origin. In short, healthy bird habitat makes for healthy human habitat.”
Next, you can set your calendar to hawks. They’ll be on the move soon. Here in Vermont, the first wave of southbound Broad-winged Hawks usually happens on the first cool, clear day during the second week of the month, usually after September 9 or so. When the north winds blow, be ready with help from my Hawkwatching Confidential.
Finally, below this immature Red-tailed Hawk, we’ll cling to summer with a slide show of images.
Red-tailed Hawk (without a red tail) / © Bryan Pfeiffer
Here’s a Brown Booby from Hawaii (not New York or Vermont).
THE BIG, BREAKING BIRDING NEWS in Vermont and New York is a Brown Booby at the Lake Champlain Bridge at Crown Point, NY.
Noted for a gangly apperance, big feet and spectacular plunge-dives, Brown Boobies occasional stray north – mostly along the US coasts.
For the state listers among you, this booby is indeed visting the Vermont side of the lake. Here’s a dynamic map of Brown Booby sightings across the continent. And here’s Ron Payne’s photo of our particular oddball visitor, which was first discovered Saturday and seen by many birders on Sunday. If it’s around today, I’ll update this post as soon as I get a report.
I chased no booby on Sunday. I went out instead for berries. Now awating a romp with your palate is one of our most spectacular summer fruits: Creeping Snowberry. You gotta eat this thing. Here’s my over-the-top (and warranted) ode to a tiny white fruit.
During a high traverse on the Worcester Range in central Vermont yesterday, Ruth and I found a bumper crop of these natural “Tic Tacs.” But don’t wait to find your own. We’ve got another week or two of snowberry season.
Our day on the trail began with with the sunrise from White Rocks (just south of Mt. Hunger), where we had spent the night watching stars.
BEFORE I LOSE IT OVER ZEBRAS, you must understand one thing about dragonflies: Not all dragonflies are created equal. Check that. Actually, they weren’t created at all. Not all dragonflies are descended equally from a common ancestor – at least in the eyes of characters like me who chase these insects to the far corners of the planet. As I see it, some dragonflies are more equal, more electrifying, more everything, than others.
My example is Zebra Clubtail (Stylurus scudderi). That’s him above from Lewis Creek in Starkboro, Vermont, last week. When I saw this dragonfly, I wet my pants. Okay, I was standing in Lewis Creek, so that’s actually how I wet my pants. But this dragonfly makes me euphoric. And I’m not entirely sure why. So I’m developing a theory on wildlife and aesthetics.
The theory begins with this hypothesis: rarity bestows beauty. Wildlife that we rarely get to see, the odd and elusive, looks to us inordinately beautiful when we actually see it in the field. We must know in advance of the critter’s scarcity for this condition to work.
Ring-billed Gull and Black-tailed Gull
The beauty that rarity bestows, however, isn’t always warranted. Take Black-tailed Gull. It lives in east Asia. It’s rare here in the U.S. Really rare. So when a Black-tailed Gull showed up in Charlotte, Vermont, in October of 2005, birders in droves came to see it. This gull should have been in the Sea of Japan rather than on the shores of Lake Champlain. It was a big event. And as the gull, acting like any other gull, sat there before the besotted crowd and a battery of expensive optics, I recall at least one of those birders gushing, “It’s so beautiful. It’s such a beautiful gull!”
Really? Any more beautiful than the common Ring-billed Gulls with which this Asian was consorting that day? Maybe the red tip on a Black-tailed Gull’s bill beats the ring on a Ring-billed Gull. Maybe. But I find our common Ring-bill more elegant. Rarity bestows beauty, even if it’s unwarranted.
Twelve-spotted Skimmer (above) and Widow Skimmer (below) / © Bryan Pfeiffer
Which brings me to Zebra Clubtail. Remember, not all dragonflies are equal. Some fly around your pond edge in abundance and sit there like Ring-billed Gulls. They’re the sparrows of dragonflies. I enjoy them nonetheless. I’ve spent many hours bringing these backyard dragonflies to life and light through photography, including the two images I’ve posted here of common beasts going by the names Twelve-spotted Skimmer (Libellula pulchella) and Widow Skimmer (Libellula luctuosa). They are fine dragonflies; I’m glad to have them among our fauna.
But they’ve got nothing on Zebra Clubtails.
Zebra Clubtails belong to a genus called Stylurus. The name might derive from “stylus” – or needle – because some of them have long, elegant abdomens (rather than the club-like abdomen displayed in our Zebra Clubtail). We’ve got only 11 Stylurus clubtails in the US (30 in the world). They fly – some like cruise missiles – on rivers. And many are exceedingly elusive. There could be hundreds of these clubtails on a stretch of river, but you’ll never see one. They spend the day hanging (needle pointed downward) high from leaves on trees along the riverbank, only dropping to the river now and then to rocket around and kill something or have sex in the air way out over the middle of the river where you can’t reach them with your net or see them with your binoculars.
Stylurus clubtails can be like a prize you’ll never win, a job you’ll never get, a fruit you shall never pick. One particular species, rarely seen as an adult (even when we see scores of its nymphs – the immature form) is aptly named Elusive Clubtail – so much so that it’s hard to learn much about the habits of this particular dragonfly. We purposefully alter its scientific name, Stylurus notatus, to be “Stylurus no datus.” I myself achieved some notoriety last summer when I found and photographed the first adult Elusive Clubtail, freshly emerged and still soft, ever encountered in the province of Saskatchewan.
On a hot day, walking these sand- and gravel-bottomed streams (as I did with my pals Josh and Wally last week), beneath a rich riparian zone, is like walking on clouds. I can think of no finer way to spend a day in August. But the best thing about this pursuit is that unlike most of their congeners (their relatives in the same genus) Zebra Clubtails sometimes perch on rocks, gravel bars, fallen logs and stout twigs beside the stream. And seeing a Stylurus clubtail in plain view is like gazing at the aurora borealis or at a solar eclipse, at a supermodel or a Hell’s Angel, for as long as you care to look. It is immeasurably satisfying, so much so that you feel you must avert your gaze, that you are unworthy of this beauty or rarity.
Is it the rarity bestowing this beauty? Perhaps not. Casual observers of dragonflies might see in Zebra Clubtail nothing particularly distinctive. All summer I’ve offered blog readers a steady diet of dragonflies, including clubtails, notably in a post titled The Gomphids and another cool but gruesome dispatch called Gomphicide. To many of you, all these dragonflies look alike. And, in fact, many of them do. But zebras are nothing if not resplendent in pattern. And that, I believe, accounts for much of Zebra Clubtail’s appeal.
Relative simplicity rules in this dragonfly: black, yellow and green. No complications. And the pattern on its abdomen – those yellow bands around the base of eight of the 10 abdominal segments – is rare among dragonflies. I believe those rings account in large part for this dragonfly’s distinctiveness, appeal and shocking beauty. It’s a pattern making this insect instantly recognizable to anyone who cares to learn and look. And knowledge, knowing a species by its name, is pleasure.
Consider this comparison: Zebra Clubtail and one of its more dazzling relatives, Serpent Ringtail (Erpetogomphus lampropeltis), which I photographed in Arizona. Yep, you can’t argue with the shock-and-awe of an aqua body and blue eyes. But there is complication in the markings of this insect: no simple bands on the abdomen, no uniformity of color. Beautiful complications, to be sure, but the symmetry and patterns on the Zebra resonate with the pleasure centers in my brain and my DNA. (Click on the image for a bigger view.)
Zebra Clubtail (Stylurus scudderi) and Serpent Ringtail (Erpetogomphus lampropeltis) / © Bryan Pfeiffer
Zebra Clubtail is a damned striking animal. Perhaps, yes, because this is no ordinary clubtail – it’s a Stylurus, after all, and by no means common or one of those backyard pond dragonflies everyone sees. Even so, ignore my theory if you want and its hypothesis that rarity bestows beauty. The hypothesis is easily falsifiable and tossed aside anyway. I suspect, however, that it does apply here – at least to some extent.
Yet I need no condition of scarcity to enjoy this insect. It is plainly spectacular.
What do you think?
Zebra Clubtail (Stylurus scudderi) / © Bryan Pfeiffer
Some of the vital parts of River Bluet (Enallagma anna).
THE DIVERSITY OF LIFE IN VERMONT, at least what we know of it, is now a bit richer. Nine days after the discovery of a dragonfly not previously known from the state, we have a new damselfly as well: River Bluet (Enallagma anna). Yeah, that’s the beast above – at least an essential part of him. Mike Blust and Laura Gaudette found this damselfly on the Ompompanoosuc River in Thetford on Monday. You may recall that Laura achived notariety for discovering that new dragonfly earlier this month – Banded Pennant.
Boreal Bluet (Enallagma boreale) / © Bryan Pfeiffer
Many of you know these bluets. They’re the dainty damsels – about an inch long – that float at pond edges and streamsides. Sometimes they’ll land on your canoe or kayak. To your right is a typical bluet species, Boreal Bluet (Enallagma boreale) from a bog in northern Vermont.
Bluets embody insect diversity. And a general rule of insect diversity is that rarely is there ever just one. We don’t have only one kind of firefly in Vermont; we have about 20 different firefly species. We don’t merely have bumblebees in Vermont; we have roughly 15 distinct bumblebee species.
And now we have a 17th bluet species.
Most bluet species are indeed blue and black. Some of them appear so similar in their patterning (or “plumage” for birders) that we can’t easily tell them apart. As a result, we net ‘em and have a closer look at their, well, at their private parts.
That’s what Mike and Laura did on Monday. It’s routine. You see some bluets, and if you don’t have binoculars or you’re past 50 and forgot your eyeglasses, you net a few and have a look at their “appendages,” their nasty bits. It’s our idea of a good time on a lake or river.
Pictured to the left are the terminal ends of various male bluet species; among many, the most distinctive characteristic isn’t the color pattern, but rather those odd, clamp-like appendages. Those appendages are what we seek out when we identify these little blue damselflies.
When he netted a bluet on the Ompompanoosuc, Mike fully expected it to be one of the common species we find all summer in Vermont. But the moment Mike looked at the appendages through his magnifying lens, the known biological diversity of Vermont changed forever. What Mike saw is what you see in the photo at the top of this blog post. In fact, we don’t even need to see the rest of the bug to know that Mike had caught Vermont’s first River Bluet. That mitten-like shape of the top appendage is diagnostic. It says River Bluet. It says it all. And nothing says it all like sex.
Males use those appendages while mating – basically as a clamp for holding females during copulation. Because many bluet species look a lot alike, and many different species can consort like folks at a nudist colony, the clamp ensures that he’s mating with a female of his own kind, a female of his own species. His clamp (actually called cerci and paraproct) fits only with the female of his species. It’s like a lock-and-key system to certify that he’s hooked up with the right female. If the clamp don’t fit, you must, uh, quit. (Sorry.)
When it fits, he’s clamped to the top of her prothorax, a section of the body behind her head – it appears he’s got her by the scruff of her neck. I’m planning a longer blog post to describe what happens next. But some of you already know – and many of you have seen dragonflies or damselflies in what we call the “copulatory wheel.”
Here’s a pair of Subarctic Bluets (Coenagrion interrogatum) in that wheel, with the male “on top” and his appendages clamped firmly behind the female’s head. These two are also linked below his mid-section, where he’s transfering sperm to the tip of the female’s abdomen. Below this dirty insect image is a photo of Mike and Laura’s now-famous River Bluet (Enallagma anna) in the hand.
By the way, I’ll see if I can determine who was the Anna for which this damselfly is named. In any event, Mike says, “Somehow it seems odd to be flaunting anna’s male parts.”
Subarctic Bluets (Coenagrion interrogatum) copulating / © Bryan Pfeiffer
Vermont’s first River Bluet (Enallagma anna) / © Mike Blust